Diffusers: The Key To Efficient Aeration

All
bubbles are not created equal; use the right diffuser for your aeration
projectOf course the
heart of any aerator has got to be the compressor, linear air-pump, regenerative
blower or windmill bellows but let's not forget to look at the myriad array
of diffusers.

The diffuser is what breaks up the airflow into bubbles! Big bubbles,
small bubbles and even micro-bubbles or ultra fine bubbles all can
be used to achieve different results.

Just like a home
stereo system can sound great through a set of high quality speakers
even if the turntable is marginal; so too can a proper diffuser make
an old homemade air pump actually create some decent aeration!

Many aeration
supply firms and pond stores sell cheap diffuses and some of these are just
that: cheap!

Maybe they'll last a year or maybe two, but as with any part of the
aeration system, whether it is changing the worn out pistons on a
Gast compressor or replacing the worn carbon vanes of a Brookwood
compressor, a diffuser may need periodic cleaning with muriatic acid.

A good diffuser assembly can be a weighted disc system like the Vertex
CoActive Air Station with 2 nine inch diffuser discs on a hollow base
that can be filled with rocks to keep it on the bottom or a Koenders
Airstone which is simply placed in to a bucket with some stones and
lowered in to the pond.

There are also many knockoffs of high-quality diffusers by companies
trying to market a poorly performing copy of a brand name technology
in order to garner greater profits. Let's look at some of the different
pond diffusers:

You
want to build a home made diffuser?
No you don't...you only think you do!

The idea of scrounging through the tool shed for some pits of PVC
pipe or hose and some metal jugs or gathering buckets and attempting
to fasten a sealed skin from some recycled EPDM membrane might sound
like a good idea but it isn't. Sure you can take some SCH 40 pipe
and drill some holes in it and cap of the end and epoxy glue a 3/4"
NPT air supply connector and make some contraption that will release
bubbles but that doesn't mean you will have an efficient diffuser.

The best diffuser is one that uses the available airflow and horsepower
to maximum efficiency but breaking up the air into bubbles...but not
all Bubbles are created equal. I know...it sounds discriminatory but
it's the Truth! In most cases you want to have small bubbles and the
smaller the better. Ultra-fine bubbles or micro-bubbles as they are
sometimes called in the industry are what creates the most efficient
aeration.

Diffuser Discs Normal airflow range is 0–5 cfm.

Equipped with 3/4" MNPT. Single disc or multiple discs can be
used with linear air pumps, piston pumps, rotary vane pumps
or regenerative blowers.

Much of the actual oxygen transfer in to your pond
or lake actually occurs at the atmosphere/water interface where water
is introduced to the atmosphere by being pushed towards the surface
by the rising bloom of bubbles.

As the water breaks the surface tension of the pond or lake the oxygen
transfer occurs and the water, now with higher levels of vital oxygen,
descends back in to the depths where it causes dissolved O2 levels
to be higher and higher depending on temperature and barometric pressure
among other variables.

But that doesn't mean you can just drop an open ended length poly
irrigation pipe running in to the pond from the end of a tire pump
and expect these basketball sized bubbles to create enough lift to
properly aerate...no...it's not that simple because the bubble size
also plays an important role in the Gallons Per Minute lifted towards
the surface and the important oxygen transfer that occurs between
the thin walls of the bubbles themselves as they stream upwards from
the diffuser towards the surface.

Yes it is a multifaceted process and while it may be sounding too
complex there is a simple rule that applies to most pond diffusers..

Smaller bubbles are better bubbles
Let's have a brief lesson in fine bubbles, it will be fun (well...not
exactly) and you will get a short course in why smaller is sometimes
better especially when it comes to diffuser bubbles.

Lesson 1
Let's take a fairly large bubble as far as aeration goes. Our large
galloping bubble that is 0.8" in diameter, just over 3/4 of an
inch, or 20 mm has a full volume of 1.64 cubic inches or 4.19 cubic
centimeters. This same glorious orb has a surface area of 5 inches
or 12.6 square centimeters and that is what we can define as a coarse
bubble!

Lesson 2
Now a coarse diffuser like an airstone would create large bubbles
like in lesson one but if we could use the same volume of air but
break that large sphere into smaller ones we could greatly increase
the available surface area which in turn enhances and embellishes
the aeration transfer capacity of the same air volume! If we replaced
that one large 3/4" wide bubble with tiny bubbles or micro-bubbles
that were 1/16 of an inch or 3 mm in diameter we could fit 296 of
these fine bubbles into the larger one of lesson 1!

The combined surface area of those 296 bubbles works out to over 33
square inches or 84 square centimeters! This is close to 7 times the
total surface area...and the surface is where the oxygen transfer
occurs.

Lesson 3
Now since the surface area is close to 7 times greater we can theoretically
aerate 7 times as much water with the same compressor or blower or
air pump depending on whether we have a fine bubble diffuser or a
coarse bubbler. Same air pump, totally different efficiency!!

Diffuser
DiscsNormal
airflow range is 0–5 cfm. Equipped with 3/4" MNPT. Single disc or multiple discs can be used with linear air pumps, piston
pumps, rotary vane pumps or regenerative blowers. Ideal for everything from
small ponds to large lakes.

Practically invisible due to their dark color, these 9 inch
membrane discs are engineered for extended performance. The actual
disc diffuser bodies are made of high-strength polypropylene with
3/4" MNPT connections to attach to airlines, manifolds or headers.
Each diffuser has an average of 6,600 engineered air release orifices,
20% more than some comparable models.

The special design of the mat, flexible and supple EPDM membrane,
with its proprietary thickness taper, results in full utilization
of the membrane surface, even at low airflow operations.

This results in improved oxygen transfer efficiency, along with maximum
operational flexibility. The disc diffuser has an integral "triple"
check valve to prevent fluid backflow. Resistance is about 10" H2O
when clean. Made in USA. Note: Diffusers are also known as airstones,
these are membrane diffusers with an EPDM fine bubble perforated system.

Airstones
These are highest-quality ceramic-type air diffusers machined from
a solid block of glass-bonded silica. Because dust and dirt particles
up to 30 microns in size will pass right through these diffusers,
there's no need for expensive air filters.

And with an air resistance of less than .25 PSI, these glass-bonded
diffusers are compatible with economical low-pressure blowers. They
produce a uniform medium/fine bubble and are very resistant to clogging.
And when cleaning does become necessary because of a buildup of calcium
precipitate or bacteria, an acid bath restores them to like-new performance.
Made in USA.

With their round grain pore structure, low resistance to airflow,
uniform porosity and resistance to clogging, these airstone diffusers
are clearly the best diffusers available for general aquaculture aeration.

Smaller pores don't necessarily produce smaller bubbles. These diffusers
are engineered to produce the smallest bubble possible within the
constraints of a reasonable service life. In most soft water applications,
they won't need to be cleaned for more than a year. Note that water
pH in excess of 9.0 will shorten the diffuser life. Self-weighting
when used with typical tubing lengths.

Airlift Synergistic DiffusersNo
need to add sand or rocks in to a hollow base like so many diffusers! These
diffusers assemblies need no extra weights! Normal airflow range is 1.5
- 2.4 CFM. Equipped with 5/8" barbed connector. These weighted diffusers lay flat upon the lake or pond bottom so disturbed
sediments is minimized and airstones do not become fouled or covered in
muck due to the underlay which keeps the airstones out of the sediment.

This synergistic diffuser assembly has some of the smallest and finest
bubbles available in any diffuser means that you get the most lifting
of water column towards the surface and less pressure loss during
operation. These diffuser assemblies require less PSI and so are perfect
for linear air pumps in most ponds

They are also the best choice for deep ponds and lakes and for storm
water retention ponds and commercial and industrial aeration.

Can also be used with rotary vane compressors, rotary screw pumps
and high pressure blowers or piston compressors for a simple and easy
aeration system. The flat base has holes for attaching mooring ropes
if you wish to add a float to the diffuser for future retrieval or
removal or replacing of the diffuser. You can also tie a float a few
inches below the surface so you don't have to see the float. The dark
color of the sediment-preventing base ensure the diffuser assembly
remains invisible.

Some of the smallest and finest bubbles available in any diffuser means
that you get the most lifting of water column towards the surface
and less pressure loss during operation. These diffuser assemblies
require less PSI and so are perfect for linear air pumps in most ponds!
Can also be used with rotary vane compressors or piston compressors
for a simple and easy aeration system. Contact us if you have questions
or unsure how many to add to your pond. See
other diffusers for small ponds or wastewater. .

The Lake and Pond Management Guidebook is the successor
to the bestselling Lake Smarts: The First Lake Maintenance Handbook,
the "bible" for small-scale lake and pond improvements, published
by the Terrene Institute in 1993.

Completely revised and updated, now published by Lewis Publishers,
this guidebook contains over 300 ideas and projects including
step-by-step practical, low-cost solutions to a wide range of
problems that lake management professionals face everyday.

Lake associations and citizens play a vital role in protecting
and restoring our lakes and waterways.

This book is an introduction to understanding and managing lakes.

Lakes and their watersheds are natural treasures for us to use
and protect. Together these rich resources supply abundant water
to support thriving communities, provide recreational opportunities,
and spur economic growth in an area.

Compare
Diffusers
When comparing aeration systems it is a good idea to look for forums
and reviews that discuss the pros and cons of various systems. Since
the principals of aeration are scientific and many companies offer
products that do basically the same thing to various degrees of efficiency
then it is up to us as consumers to use our due-diligence before buying
a pond aerator. To compare prices with our recommended systems we
have grouped some of the more popular bottom-diffuser aerator brands
together for comparison with our best aerator systems.

Compression molding ensures that we produce a part with even
specific gravity and uniform tear resistance. Other molding
techniques such as injection molding produce similar looking
parts, but the tear resistance of a compression molded part
is multidirectional, whereas the tear resistance of an injection
molded part tends to be unidirectional just like wood which
has a grain. There is an art to using just the right amount
of plasticizer in an EPDM membrane. Use too much, or the wrong
type, and emulsifying fats can leech plasticizer and cause shrinkage
and increase hardness. Use too little, and the rubber loses
its memory, bubble size increases, and the membrane is at risk
for flexure failure. Available
at: www.pumpstoreusa.com

Airstone,
Koenders Airstone, Windmill Air Stones
Aluminum Oxide Airstones Unlike the standard silica airstones
these airstones can be cleaned time and time again without wearing
down. These airstones are actually constructed of the same material
used for grinding stones. While increasing durability there
has been nothing sacrificed in the quality of aeration delivered
to you pond, tank or lagoon. We have also design an airstone
specifically designed to work well in an earth pond. These 7"
diameter dome airstones have a plate on the bottom to prevent
the airstone from digging into the pond and burying themselves
in the pond.

Claims:
Use to diffuse the air at the bottom of the water source. Aeration
is most effective when air bubbles are very small. Small bubbles
increase diffusion of oxygen from the air into the water. Can
increase oxygen absorption (your aeration process) efficiency
by 800%. Will outlast rubber diffusers. Our Experience: Poor
performance, cheap price, you get what you pay for! Available at: www.fishfarmsupply.comwww.koenderswindmills.com

AquaAirTM provides ponds and lakes with superior aeration, circulation,
and de-stratification. The diffusers employ a super fine micro-bubble
technology resulting in the highest diffuser oxygen transfer
rates (OTR) available today. The micro-bubbles entrain bottom
water and synergistically lift it to the surface where atmospheric
oxygen is absorbed and then transferred throughout the water
column.

This one really circulates your pond or lake!We've searched far and wide to come up with a rubber membrane diffuser that can generate a ton of air! What's even better is that this is a low psi design, which means your windmill or electric aerator doesn't have to struggle to open up the perfo..

This synergistic diffuser assemby has some of the smallest and finest bubbles available in any diffuser means that you get the most lifting of water column towards the surface and less pressure loss during operation. These diffuser assemblies require less PSI and so are perfect for linear air pum..

Instead of airstones these diffusers use a flexible membrane EPDM membrane to resist clogging and fouling. These are the recommended diffuser in ponds or lakes that have a high level of organics or nutrients.
Includes check valve to prevent water from filling air line when not in use. Polyet..

This synergistic diffuser assemby has extreme pumping ability and comes with a weighted base for easy installation in pond aeration. Efficient multi-airstone diffusers with the finest micro-bubbles available small ponds and koi ponds. These diffuser assemblies are perfect for linear air pumps and..

9" diffuser disc. Normal airflow range is 0–5 cfm. Equipped with 3/4" MNPT. Single disc or multiple discs can be used with linear air pumps, piston pumps, rotary vane pumps or regenerative blowers. Ideal for everything from small ponds to large lakes. Contact us with questions.12" Diffuser Discs ..

Versatile EPDM rubber membrane air diffusers can be fitted to a number of custom aeration and mixing situations. Much easier to clean than traditional silicate airstones these rubber tubes have surgical perforations for extremely small bubbles and are less prone to breakage compared to formed sol..

Fine bubbles when performance is demanded. With their round grain pore structure, low resistance to airflow, uniform porosity and resistance to clogging, these airstone diffusers are perfect for general aquaculture aeration and pond and lake aeration. These diffusers are engineered to produce ext..

ThePondReport.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com. Read our disclosure policy regarding the affiliations and commercial incentivizations of The Pond Report web site.